'compare the difference between' is grammatically correct and is a widely used phrase in written English.
For example, "Compare the difference between the two novels to understand how the authors use similar themes in different ways."
The Student's t-test was used to compare the difference between two different groups.
To compare the difference between the slopes of different regression lines, we used an appropriate form of Student's t-test (Glantz 2002).
Wilcoxon matched pair test was performed to compare the difference between EMA test results repeated for children at different ages.
These annual figures also allow us to compare the difference between average earnings and median ones, to show just what "middle Australians" are earning.
We will also compare the difference between small scale but rigorous cohort study, and large scale but noisy real world data study.
First, we compare the difference between the two main way to aid design: behaviour-simulation and knowledge based system.
A calculator on Finaid.org, a site created by Mr. Kantrowitz, can help compare the difference between a standard repayment option and an income-contingent option.
If you compare the difference between Romney's margin among Catholics in 2012 and Trump's margin among Catholics this year, the 25-point difference is tied for the biggest shift of any demographic group in the Post-ABC poll.
The method allows to appraise and critically compare the difference between the strength obtained from drilling tests and the one measured on the specimens sampled during the casting.
How the post-cam design affects knee kinematics is still unknown, particularly, to compare the difference between the two design features.
Another 2D-OHP with same turns and similar geometry size as 3D-OHP was also tested to compare the difference between two OHPs.
